Why is it important that the phospholipid bilayer be both hydrophobic and hydrophilic?

it is not important

to maintain a proper internal environment

to link cells together

The answer to your question is:  The second option is correct.

Explanation:

Pospholipid bilayer is a thin lipid layer that protects and isolate the cell from the enviroment, also it controls the the entrance of molecules to the cell  and ejects wastes. So it is extremely important.

it is not important    This could not be the right answer, bilater is very important.

to maintain a proper internal environment  I think this is the right answer because among others, membranes mantain a proper internal environment.

to link cells together This option is incorrect, because membranes do not link   cells.

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.